Advanced Diagnostic Laboratories

Collect

Red top tube or SST

Specimen Preparation

Allow sample to clot at room temperature for 20 to 60 minutes.  Centrifuge ASAP to separate serum from cells and aliquot cell-free serum into a labeled polypropylene or similar plastic tube.

Patient Prep

None

Pediatric Collection

0.5 mL

Unacceptable Conditions

Clotted or hemolyzed samples, plasma

Storage Transport Temp

Send serum Priority Overnight via FedEx and in a well insulated container with an ice pack or frozen on dry ice.

Stability

2-8°C for 48 hours, >1 month at -70°C

Performed

Mon-Fri

Methodology

ELISA followed by confirmation by flow cytometry.

Reported

14 days

Department

Immunology Lab - Functional Assay

Synonyms

PAP, pulmonary alveolar proteinosis, intracellular infection, GMCSFA

Related Tests

IFNGAB

Reference Interval

Negative

Interpretation

Granulocyte-macrophage colony-stimulating factor (GM-CSF) promotes the proliferation and differentiation of hematopoetic cells including macrophages, neutrophils and dendritic cells.  Neutralization of GM-CSF activity can therefore impair the development and/or function of these cell types.

Neutralizing anti-GM-CSF autoantibodies are associated with pulmonary alveolar proteinosis (PAP), a rare lung disease that is characterized by the inability of macrophages to clear surfactant from the alveolar lung spaces.  Additionally, anti-GM-CSF autoantibodies have been noted in patients with opportunistic infections with intracellular organisms such as M. avium complex, Cryptococcus, Nocardia and Aspergillus species.  It is possible that neutralization of GM-CSF in vivo leads to compromised macrophage function which is a key component of the immune response to intracellular organisms.

Anti-GM-CSF autoantibodies are detected by an initial screening ELISA.  If the result is positive, the test reflexes to a flow cytometry assay to determine the ability of the autoantibody to neutralize GM-CSF.  Low titer, non-neutralizing autoantibodies may be detected in healthy individuals.  Clinically significant anti-GM-CSF autoantibodies are reported when both the ELISA and the abilty to neutralize GM-CSF are positive.

References:

Kitamura, T., et al. Idiopathic pulmonary alveolar proteinosis as an autoimmune disease with neutralizing antibody against granulocyte/macrophage colony-stimulating factor.  The Journal of experimental medicine. 1999; 190:875-880.

Bonfield, T. L., et al. Anti-GM-CSF titer predicts response to GM-CSF therapy in pulmonary alveolar proteinosis.  Clinical Immunology. 2002; 105:342-350.

Rosen, L. B., et al. Anti-GM-CSF autoantibodies in patients with cryptococcal meningitis.  Journal of Immunology.  2013; 190:3959-3966

 

CPT Code

83516- ELISA
86353,88184,88185- Flow reflex